Sorry to do this, but you guys are like walking dictionaries and I don't quite understand the concept...

anyhow, I'm getting this Iro Crank: 130bcd with alloy 46 tooth ring, and I'm wondering what size cog to get.
I'm tall, I'm new to fixed gear, I'm going to be using a 170mm crank, and I live in ohio which is very very flat.

So what would you recommend? thanks.